The biggest weapon in the war on muscle drugs isn't the cops. It's a clever scientist in a Los Angeles lab

There was no way to be sure what was in the mysterious vial that arrived in Dr. Don Catlin's Los Angeles lab last June. All he knew was that he had been told to find out what it was--and if it was what he suspected, it could mean big trouble for a lot of people.

That trouble arrived earlier this month when the Department of Justice announced that it was charging four San Francisco--area men with 42 counts of conspiring to distribute anabolic steroids and other performance-enhancing drugs--the charges stemming, in part, from what Catlin found in the vial. Things heated...